As an example of prior art motor driving apparatus used for an electric vehicle or HEV (Hybrid Electric Vehicle), there is a motor driving apparatus disclosed by patent reference 1. This motor driving apparatus is provided with a motor, an inverter for converting direct current power into AC power, a high-voltage battery, a DC/DC converter, and a DC link capacitor. The DC/DC converter raises a voltage furnished from the high-voltage battery and furnishes direct current power to the inverter at the time of power running, and lowers the direct current power outputted from the inverter and furnishes it to the high-voltage battery at the time of regeneration. The DC link capacitor is comprised of a plurality of capacitors and is arranged between the DC/DC converter and the inverter so as to smooth the direct current voltage.
Patent reference 1: JP,8-214592,A
When the prior art motor driving apparatus is so constructed that the inverter, DC/DC converter, and DC link capacitor are modularized into one power converter in order to downsize the motor driving apparatus, a current pulse outputted from the DC/DC converter to the DC link capacitor and an alternating current pulse furnished from the DC link capacitor to the inverter influence each other, and therefore a ripple current which flows into the DC link capacitor increases. When the related art motor driving apparatus is so constructed that an amount of ripple current which flows into each capacitor is equal to or less than an allowed value in order to secure the life of the DC link capacitor, there is a problem that the DC link capacitor increases in size and hence the whole apparatus increases in size.
The present invention is made in order to solve the above-mentioned problems, and it is therefore an object of the present invention to provide a motor driving apparatus and a power converting apparatus which minimize a ripple current which flows into a DC link capacitor thereof, and which decrease in size.